Abstract
High-temperature oxidation behavior of Inconel 625 superalloy manufactured by wire arc additive manufacturing (WAAM) technique was investigated. Results showed that microstructure of the as-built alloy contained Ni-based solid-solution dendrites along with MC carbide, Laves, and δ phases. Holding of samples at 800–1000 °C for 20 h resulted in the formation of Cr2O3 and Ni3Nb phases on the surface of the alloy. However, at 1100 °C, oxidation of Ni3Nb led to the formation of CrNbO4 at the oxide/alloy interface. The growth kinetics of the oxide layer followed a parabolic law, and the
diffusion activation energy was calculated as 167 kJ/mol.
